Eurofins Biomnis code

WIL

Synonyms

• Factor VIII-related antigen
• Ristocetin cofactor
• von Willebrand - factor
• Von Willebrand factor
• VWF:Rco
• VIII R (related)-Ag

Clinic significance

Von Willebrand's disease is a congenital haemorrhagic diathesis (generally inherited as an autosomal dominant), reported to affect 1% of the population and caused by a quantitative or qualitative von Willebrand factor anomaly. Von Willebrand factor has two main functions: it is involved in interactions between platelets and the damaged vascular wall and transports and protects factor VIII in plasma. This accounts for the bio-clinical signs of the disease: increased bleeding time, a prolonged partial activated thromboplastin time and excessive mucosal and cutaneous haemorrhage following minor injury. Biological diagnosis is essentially based on assays of Factor VIII and von Willebrand Factor (activity and antigen). These tests cannot be performed in patients with ongoing inflammatory processes or in pregnant women. Moreover, the patient's blood group must be taken into account because normal Group O subjects habitually have lower levels of von Willebrand's Factor than others.

Prenalytics

• 2 mL
• Citrated Plasma
• FROZEN

Further information

• Plasma with platelets removed by double centrifugation: 2500 g 15 min
• Send us the ABO blood group result. For desmopressin testing (Octim®, Minirin®) please indicate the time period for each tube (T0, T+1hr etc.)
• Could you please provide the us the PFA-100 result, if available
• It is advisable to send us a frozen and centrifuged citrate sample in compliance with the GFHT pre-analytical recommendations.
• Enclose the specific clinical information form (R5-INTGB : Haemostasis)
• In the event of screening for von Willebrand disease, ristocetin cofactor activity and factor VIII coagulant activity are carried out first. Von Willebrand factor antigen is performed only performed if the functional assay (activity) is decreased

Documents to download

• Specific clinical information form (R5-INTGB)

Methodology

Immunological turbidimetric method

Turnaround time

2 days